Regenerative gas turbine



June 1, 1965 J. P. MILLER REGENERATIVE GAS TURBINE 3 Sheets-Sheet 1 Filed Aug. 24, 1962 June 1, 1965 J. P. MILLER 3,186,478

REGENERATIVE GAS TURBINE Filed Aug. 24, 1962 3 Sheets-Sheet 2 INVENTOR.

hwy/2 F/V/F/Ye/ BY TO RNEY 3,186,478. REGENERATIVE GAS TURBINE Joseph P. Miller, lndianapolis,'lnd., assignor to General Motors Corporation, Detroit, Mich a corporation of Delaware Filed Aug. 24, 1962, Ser. No. 219,319

I Claims. (Cl. 1657) My invention relates generally to gas turbines incorpor ating rotary regenerators'and, in a more exact sense, to rotary regeneratorshaving improved characteristics for use in heat exchange betweenfiuids at significantly different pressures, as in gas'turbines. v I i Rotary regenerators ofboth axial-flow and radial-flow types are well known, and have been employed for such purposes as air preheaters and as regenerato rs for gas turbines. Such a regenerator embodies a housing within which a porous matrix, usually a disk or drum, is rotated slowly. The housing defines two zones for passes for the fluids which are in heat exchange relationship, and the matrix inits rotation moves each portion of the matrix successively through the two zones. .A wall which may be called a diaphragm or bulkhead separates the two Zones. To prevent undue mixture or leakage of fluids, a seal which may be called a diaphragm seal is provided at the two points where the matrix passes through the diaphram.

In the usual gas turbine installation, air flows from the V compressor to the combustion apparatus through one zone of the matrix and flows from the turbine to the engine exratio engine, there will ordinarily be some two or three atmospheres pressure diiference between the compressed air and the exhaust gas. This pressure differential acts over the cross-sectional area of the matrix where it passes through the diaphragm generating a force perpendicular to the diaphragm and proportional to the product of the cross-sectional area of the matrix and the pressure differential. Obviously, these gas load forces may be quite substantial.

One well known regenerator, described in United States Patent No. 3,057,604, supports the matrix by rollers bearing against the rim of the matrix at its low pressure side, with the result that this gas load presses the matrix against the supports. in this construction, and also where the matrix is supported by a central shaft,.relative thermal expansion of the matrix and housing requires considerable flexibility of the mounting of the seals in the housing.

As the cross-sectional area of the matrix increases and as the pressure ratio of the engine increases, the gas load increases and may become sufficient to cause quite undesirable loads on the matrix supports.

In accordance with my invention, means are provided to counteract the gas load on the matrix, preferably rollers which engage the matrix rim, or its shaft if one is provided, and which are acted upon by a piston or motor which responds to the same pressure difference which acts on the matrix. This makes it possible to obtain a substantially constant relatively light load on the matrix supports. It also makes it feasible to support the matrix at points closely adjacent the diaphragm so that very little relative displacement of the matrix and the housing can occur where the diaphragm seals are mounted. With an external matrix support adjacent the diaphragm, the gas load tends to lift the matrix from the support. However, when the gas load is counteracted, a relatively small spring force or the weight of the matrix may be relied upon to retain the matrix against its support.

Particularly where the matrix is rim-driven by pinions acting upon a ring gear on the matrix rim, there needs to be some force to hold the pinions and ring gears in mesh.

The foregoing should indicate clearly the general nature invention.

. 2 of my invention and serve to introduce the succeeding detailed description of the preferred embodiment which will further disclosethe nature and the, advantages of the The principal objects of the invention are to improve the performance of rotary regenerators and increasethe endurance of such devices, and to facilitate more efiective sealing of the regenerator matrix.

Referring to the drawings:

FIGURE 1 is an elevation view, with parts in section,

of a gas turbine engine incorporating the invention.

7 FIGURE 2 is a transverse sectional view of the same,

taken on the plane indicated by the line 2-2 in FIG- URE 1.

FIGURE 3 is an enlarged view corresponding to a portion of FIGURE 2.

FIGURE 4 is a fragmentary plan view, with parts in section, taken on the plane indicated generally by the line 4- -4 of FIGURE 2.

While the structure of the engine apart from the re-.

\ describedbriefly, with reference to FIGURES 1 and 2.

haust through the other zone. Even in a low pressure The engine includes a compressor 10 having an air inlet 11, an axial flow section 12, and a radial flow section discharging into a diffuser scroll 13 which is connected to inlet spaces or cool air spaces 14 of a rotary regenerator indicated generally by 15. In this case, the regenerator is a dual one having two drum-type annular rotary matrices 16 which are nearly coaxial with the compressor 19.

I The compressor discharge air flows through the matrix 16 into a plenum or hot air space 17 within the matrix,-

10 through a shaft 21, the other of which drives a power flow radially outward through the matrix 16 into an exhaust or cool gas space 31 outside of the matrix and discharge through outlets 33. The compressor scroll 13 and reduction gear 24 bolt to an end plate 32 to which the lower or forward margin of the diaphragm 26 and also the upper edge of the scroll 29 are fixed. The regenerators are enclosed by a roughly cylindrical housing 34, the rear end of which is closed by a cover 36 oven an opening large enough for installation and removal of the matrix. The smaller cover or support plate'19 on the plate 36 supports the rear ends of the combustion chambers 18. The upper or rear edge of the diaphragm 26 is fixed to the cover plate 36.

From FIGURE 2, which provides an and view of the forward matrix 16, it will be apparent that approximately one-third of the matrix is located below the diaphragm 26 in the compressed air zone and the remainder of the matrix lies in the exhaust gas Zone above the diaphragm. A main seal 38 is provided for each matrix at the point where it passes through the diaphragm. Details of this seal are unimportant to this invention, but they may, for

example, be similar to those of United States Patents No. 2,888,248, and No. 3,057,604.

As is customary, rim seals are provided to prevent the air or gas from bypassing the matrix. As shown in FIG- URE 1, a ring of rim seals 4 is mounted on the front plate 32 and a similar ring 41 on the rear cover 36. A

ring 43'suitably supported in the housing between the matrices mounts rim seals 44 on each side.

Each matrix 16 has a rim 4-6 at each end against which the rim seals bear. The rim mounts a circular ring or track 47 and a ring gear 48. These cooperate with the driving and supporting mechanism for the matrix. Suitable porous material in the form of plates or elements 49 extending between the rims constitutes the heat exchange material of the matrix. This matrix structure is simply exemplary and may be varied as desired.

FIGURE 2 shows the supporting rollers 50 and 51 .for the front end of the forward matrix, those for the rear end and the rear matrix being similar. .This structure may also be much like that of United States Patent compressed air zone of the regenerator.

It will be apparent that the difference in pressure between the compressed air zone below the diaphragm and the exhaust gas zone above the diaphragm generates forces on the matrix perpendicular to the diaphragm at the points where the matrix passes through the diaphragm, these forces being equal to the product of the pressure diiferential and the area acted upon. or compensated, these forces would tend to lift the matrix from the drive rollers and jam it at the seals 38. In accordance with this invention, loading means are provided to counteract this gas load and to retain the matrix in engagement with the drive means with sufficient but not excessive force. Referring generally to FIGURES 1 and 2, and to FIG- URES 3 and 4 for the details, this means comprises an expansible chamber motor 60 in the upper part of the housing 34, a lever 61 in the form of a rhomboidal frame biased by the motor and fulcrumed on a support 63, and bogies 64 mounted on the lever 61 and bearing against the matrix 16. The fulcrum 63 comprises a screw 66 threaded into a bracket 67 in the housing, the end of which is received in a socket 68 at one end of lever 61. Similarly, the other end of lever 61 has a socket 69 receiving the pin 70 rigid with the piston 71 of the motor 60. The piston '71 is reciprocable in cylinder 72 of the motor and is piloted in head 73 of the cylinder, the resulting small chamber 74 having a dashpot or damping effect on the piston. Piston 71 is biased downwardly by two Belleville springs 76 and by compressor discharge pressure of the engine tapped off at any suitable point and introduced into the cylinder through a pipe 77. The lower end of the cylinder is referenced to exhaust zone pressure through an opening 78. The force exerted by the motor 60 on the end of lever 61 is proportional to the same pressure differential as that providing the gas load on the matrix. This force is communicated to the matrix by the bogies 64, each of which is provided with two rollers 80 engaging the ring 47 of the matrix. Rollers 89 are integral with shafts 81 j-ournalled in bushings 82 of the body 83 of the bogie. The bodyis pivotally connected to the lever 61 by a stud 8d mounted in a bushing 87.

The effective area of piston 71 is so related to the force ratio of lever 61 and the effective area of the matrix cross- 7 section that piston 71 exerts. a force on the matrix subchanges in compressor speed, atmospheric pressure, etc,

which vary the pressure differential.

If not corrected ture. Changes in diameter of the matrix because of relative heating and cooling are accommodated by slight movements of piston 71, so there is no binding and the matrix is free to expand and contract.

It will be apparent from the foregoing to those skilled in the art that my invention results in improved operation of the regenerator; it reduces bearing friction and difficulties with the sealing of the matrix, and it thus acts to improve the efficiency of the engine.

The detailed description of the preferred embodiment of my invention for the purpose of explaining the principles thereof is not to be regarded as limiting the invention. Many modifications of structure can be made by the exercise of skill in the art within the scope of the invention.

I claim: 7

1. A rotary generator comprising, in combination, a housing, a diaphragm dividing the housing into two zones, a porous regenerator matrix symmetrical about an axis of rotationrotatably mounted in the housing and extending into both zones, the matrix being traversed between the zones by rotation about said axis; the diaphragm having structure providing clearance for movement of the matrix between the zones, the regenerator being adapted for use in a system normally establishing a pressure 'in one zone which is greater than the pressure in the other zone so that a pressure differential between the zones exerts a force on the matrix transverse to said axis urging it toward the lower pressure zone, motor means communicating with said zones and responsive to any pressure differential between the Zones effective to exert a force proportional to such differential, and force applying means coupling the motor means to the matrix including means engageable with the matrix to direct a force opposed to the first-mentioned force urging the matrix toward the higher pressure zone so as to counteract the first-mentioned force.

2. A regenerator as recited in claim 1 in which the pressure differential responsive motor means includes a movable wall exposed to the pressures in the said zones, a chamber divided by said wall into two compartments, and vpassage means connecting one compartment with the higher pressure zone and the other with the lower pressure zone.

3. A regenerator as recited in claim 1 including supporting means for the matrix adjacent the diaphragm act ing against the higher pressure side of the matrix and in which the motor means acting through the force transmitting means counteracts the tendency of the first-mentioned force to lift the matrix from the supporting means.

4. A rotary regenerator comprising an annular rotatable foraminous matrix, housing means divided by a diaphragm defining separate flow paths for fluid through distinct zones through which the matrix passes during rotation, sealing means on the diaphragm sealably engaging the matrix, providing clearance for movement of the matrix between the zones, and isolating the two zones, and antifriction means supporting the matrix for rotation at the periphery thereof, any difference in pressure between the fluids acting over the cross-section of the matrix within the sealing means to bias the matrix and thereby vary the load on the antifriction supporting means, expansible chamber motor means communicating with said I zones including means defining a moving wall biased proportionately to the said diiference in pressure of the fluids, and means transmitting the force on the wall to the 3,186,478 5 6 matrix in such sense and to such scale as approximately References Cited by the Examiner t0 counteract the said bias. ST P 5. A regenerator as recited in claim 4 in which the antifriction suppolting means is closely adjacent the seal- 2,892,615 6/59 Mlserfer 165 7 ing means and the last-named means engages the matrix 5 3057604 10/62 Bubmak at 1659 approximately equidistantly from the sealing means. CHARLES SUKALO, Primary Examiner. 

1. A ROTARY GENERATOR COMPRISING, IN COMBINATION, A HOUSING, A DIAPHRAGM DIVIDING THE HOUSING INTO TWO ZONES, A POROUS REGENERATOR MATRIX SYMMETRICAL ABOUT AN AXIS OF ROTATION ROTATABLY MOUNTED IN THE HOUSING AND EXTENDING INTO BOTH ZONES, THE MATRIZ BEING TRAVERSED BETWEEN THE ZONES BY ROTATION ABOUT SAID AXIS; THE DIAPHRAGM HAVING STRUCTURE PROVIDING CLEARANCE FOR MOVEMENT OF THE MATRIX BETWEEN THE ZONES, THE REGENERATOR BEING ADAPTED FOR USE IN A SYSTEM NORMALLY ESTABLISHING A PRESSURE IN ONE ZERO WHICH IS GREATER THAN THE PRESSURE IN THE OTHER ZONE SO THAT A PRESSURE DIFFERENTIAL BETWEEN THE ZONES EXERTS A FORCE ON THE MATRIX TRANSVERSE TO SAID AXIS URGING IT TOWARD THE LOWER PRESSURE ZONE, MOTOR MEANS COMMUNICTING WITH SAID ZONES AND RESPONSIVE TO ANY PRESSURE DIFFERENTIAL BETWEEN THE ZONES EFFECTIVE TO EXERT A FORCE PROPORTIONAL TO SUCH DIFFERENTAL, AND FORCE APPLYING MEANS COUPLING THE MOTOR MEANS TO THE MATRIX INCLUDING MEANS ENGAGEABLE WITH THE MATRIX TO DIRECT A FORCE OPPOSED TO THE FIRST-MENTIONED FORCE URGING THE MATRIX TOWARD THE HIGHER PRESSURE ZONE SO AS TO COUNTERACT THE FIRST-MENTIONED FORCE. 